EFA with HEC... Do you realise how hard it is to use dual HEC while trying to manage heat properly?
OHB (OverloadedHeatBomb) is practically useless unless you're going for raid or counters. With that supreme cannon and recoiler you might as well run a burning shower build.
Take a look at what the first mech's weakness is for a claw build, no form of movement. Mighty cannon and malf blaster might be a good combi, when it's also combined with legs, since if your opponent is on range 7, you can't do much with dark eagle. Did I mention you won't need energy resistance if you don't have any energy modules at all?
Second build is just a slightly worse version of the RRSI hugger, (Red Rain Space Invader), backstabbing guardian is mainly used for EFA/magma blast & sorrow builds. Did I mention no resistance drainer?